Error "Cannot read property 'format' of undefined " about railroad-diagrams HOT 3 CLOSED

The first argument of Choice() has to be the index of which option is the "normal" option. I've added some checking and better error-messages, so your mistake gets caught upon construction and tells you what's wrong, rather than just throwing a mysterious-looking error message during .format().

from railroad-diagrams.

Excuse me for the lost of time. I do't put attention to the example of:
http://www.xanthir.com/etc/railroad-diagrams/example.html

Finally, as general reflexion, I must say that coding in JS is not tented to make validation, checking, etc. Principally because it adds more verbosity and is tedious. But, it save a lot of time when the users (pity users like me) of that library use it in his code.

from railroad-diagrams.

No problem, the error was showing up at a bad and confusing place; I'm happy to make it simpler to find this common authoring error.

from railroad-diagrams.